Use testharness.js instead of js-test.js in LayoutTests/fast/canvas tests.

third_party/WebKit/LayoutTests/fast/canvas/script-tests/canvas-getContext-invalid.js

-description("Test that invalid canvas getContext() requests return null.");
-
-canvas = document.createElement('canvas');
-
-shouldBe("canvas.getContext('')", "null");
-shouldBe("canvas.getContext('2d#')", "null");
-shouldBe("canvas.getContext('This is clearly not a valid context name.')", "null");
-shouldBe("canvas.getContext('2d\0')", "null");
-shouldBe("canvas.getContext('2\uFF44')", "null");
-shouldBe("canvas.getContext('2D')", "null");
-shouldThrow("canvas.getContext()");
-shouldBe("canvas.getContext('null')", "null");
-shouldBe("canvas.getContext('undefined')", "null");